1. Field of the Invention
The present invention relates to a film handling system provided with a safety means to advance a film properly following the prescribed sequence through each step of exposure, processing and projection of said film using one common film containing cartridge.
2. Description of the Prior Art
It has been widely accepted recently in the field of small size motion picture to load film into a camera and photographing is then accomplished. After photographing, exposed film is processed while the cartridge is kept in a camera or is moved to another device. Subsequently, the processed film is projected with a projector.
In a system for using a conventionally sold film cartridge, such typical use is that the film with which photographing is finished is sent to a prescribed developing factory where the developed film is wound on a separate reel from said cartridge, then it is sent back to the photographer either as it is or is housed in a cartridge for projection. The photographer projects the same to enjoy the same. One shortcoming in such conventional way of use is that the photographer can not develop and project the film immediately after photographing.
In a still camera in order to overcome said conventional shortcoming, technique has already been used such that a film is subjected to a developing process immediately after photographing with a camera and said developing process is completed in a camera within a short period of time thus the picture which has just been photographed can be seen. As the film after photographing is of a considerable length with a large volume in the field of small size motion picture, it has been difficult to have so-called instant developing in a simple manner as in a still camera. However, such technique has been proposed lately that a long film is housed compactly in a cartridge and said cartridge is used as it is in photographing, developing and projection so that instant developing and instant projection can be done. Such technique has been proposed by the U.S. Pat. No. 3,644,024, and 3,604,790, etc. That developing liquid is stored in a cartridge which houses film, and after all of the film is exposed, the developing liquid storage chamber within a cartridge is broken to coat the film with the developing liquid for instant developing process. Also, concerning instant developing and instant projection, such technique has recently been proposed that the above mentioned cartridge which houses film and developing liquid is mounted in a movie projection unit so that the film is dried after instant developing and is transferred to projection step.
By such technique, advantages are such that the entire process from photographing to projection can be done in a remarkably short period of time compared to conventional technique, which tends to increase the number of camera users either in a still camera or a motion picture camera. As a camera and a projector are widely spread and the range of their users is expanded, it becomes necessary to secure conveniences in handling. Therefore, for preventing erroneous handling by anyone, it is necessary to provide such means in a mechanism of a camera or a projector to prevent erroneous functioning even if a user makes erroneous handling.